Method for diagnosing a drive device of a motor vehicle, and motor vehicle

Abstract

The invention relates to a method for diagnosing a drive device (10), which has an internal combustion engine (12), of a motor vehicle that can be driven by means of an internal combustion engine (12), wherein the drive device (10) has components (60a-c), by means of which the composition of exhaust gas of the internal combustion engine (12) can be influenced and / or detected. For each component (60a-c), an electronic computing device (62) is used to carry out at least one respective diagnostic method which is assigned to each component (60a-c) and by means of which, for each component (60a-c) assigned to the respective diagnostic method, at least one respective current characteristic is ascertained which is assigned to the respective component (60a-c) and which characterizes the respective current state of the respective component (60a-c). The electronic computing device (62) is used to ascertain at least one change value of a constituent of the exhaust gas, said change value being assigned to the respective component.

Description

[0001] Method for diagnosing a drive device of a motor vehicle and motor vehicle

[0002] The invention relates to a method for diagnosing a drive system of a motor vehicle, in particular a car. Furthermore, the invention relates to a motor vehicle, in particular a car.

[0003] DE 102021 127 196 A1 discloses a computer-implemented method for diagnosing a deterioration of at least one component of a technical system.

[0004] The object of the present invention is to provide a method and a motor vehicle so that a particularly advantageous diagnosis of a drive device of the motor vehicle can be realized.

[0005] This object is achieved by a method having the features of patent claim 1 and by a motor vehicle having the features of patent claim 8. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0006] A first aspect of the invention relates to a method for diagnosing a drive device of a motor vehicle, also simply referred to as a vehicle, which is preferably designed as a motor vehicle, in particular as a passenger car. In the method, the drive device has an internal combustion engine, also referred to as an internal combustion engine, motor or internal combustion engine, by means of which the motor vehicle can be driven. The internal combustion engine can be operated in a fired mode in which combustion processes take place in the internal combustion engine, and in particular it is provided that in the method the internal combustion engine is operated in the fired mode so that the said combustion processes take place in the internal combustion engine, in particular in combustion chambers of the internal combustion engine.During each combustion process, a respective fuel-air mixture, also referred to simply as a mixture, is combusted, resulting in exhaust gas from the internal combustion engine. Thus, the internal combustion engine can provide exhaust gas. Preferably, the internal combustion engine provides the exhaust gas in the method.

[0007] In the method, the drive device has components by means of which the composition of the exhaust gas of the internal combustion engine can be influenced and / or detected. The feature that, for example, the composition of the exhaust gas can be detected by means of the respective component is to be understood in particular that at least one measured variable can be detected by means of the component, which here characterizes at least one component of the exhaust gas, thus at least one chemical substance contained in the exhaust gas, also simply referred to as a substance. The chemical substance is to be understood as an element, a compound or a mixture. During combustion of hydrocarbon-air mixtures, the exhaust gas contains, among other things, the components CO, NMHC and NOx.

[0008] In the method, at least one respective diagnostic method assigned to the respective component, also referred to as an individual diagnostic method, is carried out for the respective component by means of an electronic computing device, in particular of the motor vehicle, by means of which diagnostic method at least one respective current characteristic value assigned to the respective component, in particular a respective characteristic variable, is determined for the respective component to which the respective diagnostic method is assigned, which characterizes a respective current state of the respective component. Thus, for example, the respective current characteristic value characterizes the respective current characteristic variable that characterizes the respective state of the respective component. The electronic computing device is or comprises, for example, at least or exactly one electronic computing unit, also referred to as a control unit.Furthermore, it is conceivable that the electronic computing device has a plurality of electronic computing units, also referred to as control units, which are coupled to one another, for example, in particular via a data bus, in particular in such a way that the computing units can exchange data.

[0009] In the method, a respective change value of the component of the exhaust gas, in particular a change quantity, assigned to the respective component is determined by means of the electronic computing device for the respective component, in particular based on a respective initial value of a respective component of the exhaust gas, as a function of the respective characteristic value assigned to the respective component and as a function of at least one respective characteristic map stored in the electronic computing device, in particular in an electrical or electronic data memory of the electronic computing device, and assigned to the respective component, which map can be designed, for example, as a two-dimensional, a three-dimensional characteristic map up to an n-dimensional characteristic map and / or also as a characteristic curve,wherein the respective change value characterizes a change in the initial value that can be brought about by the respective component in its current aged or deteriorated state. The change values ​​of the various components are compared with one another by means of the electronic computing device, whereby the largest of the change values ​​is determined. For example, the characteristic map is "driven out" during the development of the motor vehicle, i.e., empirically determined and thus data-based. The respective initial values ​​of the respective components of the exhaust gas for the respective components can be determined, in particular, when the components are in a new state. For the method according to the invention, one or more, in particular differently aged and / or defective components are installed in vehicles during development in order to simulate the exhaust gas influence of various deterioration stages of the respective component or components.in particular, to determine the characteristics of the respective component or components. The information obtained is stored in at least one or more characteristic maps or characteristic curves in the data memory.

[0010] According to the invention, an entry is stored in the data memory of the electronic computing device for the component, and preferably only for the component, to which the largest of the change values ​​is assigned, and / or an indication signal that can be perceived visually and / or haptically and / or acoustically by a person, in particular in the interior of the motor vehicle, is output by means of an electrical or electronic playback device of the motor vehicle. The data memory is also designed, for example, as an error memory. The entry informs, for example, a person carrying out repairs or maintenance on the motor vehicle that the component, and preferably only the component, to which the largest of the change values ​​is assigned needs to be replaced.

[0011] Accordingly, for example, the warning signal can be used to communicate to the person perceiving the warning signal that the component, and preferably only the component, assigned the largest change value needs to be replaced. The respective change value characterizes the respective exhaust gas criticality of the respective component. In other words, the respective change value indicates how strongly the respective component or its current state affects the current composition of the exhaust gas and also the future composition of the exhaust gas, in particular negatively, so that the component assigned the largest change value has the greatest exhaust gas criticality relative to the components.The component to which the largest change value is assigned therefore has the highest or greatest exhaust gas criticality in relation to all components. Consequently, the component to which the largest change value is assigned contributes most strongly or most to an overall change in the exhaust gas, particularly in the form of deterioration, also referred to as exhaust gas change or exhaust gas deterioration. The entry or the warning signal therefore only displays the most exhaust gas-critical component. This means that in a workshop, for example, only this most exhaust gas-critical component, i.e. the component with the highest exhaust gas criticality, can be replaced in order to (once again) achieve advantageous low-emission operation of the drive system after replacing the most exhaust gas-critical component. Repair or replacement of the other components can therefore be avoided. If necessary,Later in the vehicle, the second most critical component is also stored, or even the complete ranking list.

[0012] Advantageously, all exhaust-relevant components of the vehicle are diagnosed as described.

[0013] In an advantageous embodiment of the invention, for example, the respective change value is compared with a respective assigned limit value by means of the electronic computing device, wherein the change values ​​are compared with one another by means of the electronic computing device then and preferably only when it is determined by comparing the respective change value with the respective limit value that at least one of the change values ​​exceeds the respectively assigned limit value. Alternatively or additionally, the error entry is stored for the component to which the largest of the change values ​​is assigned and / or the indication signal is then and preferably output when it is determined by comparing the respective change value with the respective limit value that at least one of the change values ​​exceeds the respectively assigned limit value.Alternatively or additionally, it can be provided that the change values ​​are summed up by means of the electronic computing device, whereby a total value, in particular a total value for each component of the exhaust gas such as CO, NMHC, is formed, which total value is compared by means of the electronic computing device with the assigned limit value, in particular a limit value for each component of the exhaust gas, wherein the change values ​​are then and preferably summed up by means of the electronic computing device if it is determined by comparing the total value with the limit value that the total value exceeds the limit value. Alternatively or additionally, an error entry is then and preferably stored and / or a further indication signal is output for the component to which the largest of the change values ​​is assigned if it is determined by comparing the total value with the limit value that the total value exceeds the limit value.This is carried out in particular for different components of the exhaust gas such as NMHC, CO, etc., whereby a separate limit value can be used for each component.

[0014] Such an exceedance of the respective limit value or threshold value by the respective total value means, for example, that an excessive change, in particular a deterioration, in the composition of the exhaust gas is predicted. The deterioration of the composition of the exhaust gas is to be understood as synonymous with a deterioration of the exhaust gas. Thus, it is preferably provided that the change values ​​are compared with one another when and preferably only when an excessive change, in particular a deterioration, in the composition of the exhaust gas, and thus of the exhaust gas, is detected. As a result, for example, the error entry or the further warning signal can be stored or displayed when and only when an undesirable, excessive change, in particular a deterioration, in the composition of the exhaust gas is detected.

[0015] It is conceivable that the formation of the respective total values ​​and the comparison of the change values ​​always takes place at the end of each driving cycle, wherein preferably the further warning signal or the error entry is issued or made when and only when an excessive change, in particular deterioration, in the composition of the exhaust gas, and thus of the exhaust gas, is detected.

[0016] A further embodiment of the invention is characterized in that the electronic computing device sorts the change values ​​in ascending or descending order by comparing the change values. In other words, it is preferably provided that the electronic computing device determines or generates a sequence, also referred to as a ranking, by comparing the change values, according to or in which the change values ​​are sorted in ascending or descending order. This ensures a particularly advantageous diagnosis and thus testing of the drive device.

[0017] The aforementioned deterioration in the composition of the exhaust gas is to be understood in particular as meaning that the amount of a component of the exhaust gas contained in the exhaust gas, also referred to as emission or emission value, is or becomes excessively large. The component with the greatest or highest exhaust gas criticality therefore contributes most strongly to the change, in particular deterioration, in the composition of the exhaust gas and thus has the greatest influence, also referred to as emission influence, on the aforementioned emission, relative to the components. When establishing the sequence, the components are sorted in ascending or descending order with regard to their respective, own, determined emission influence, whereby, for example, the component with the greatest exhaust gas criticality with regard to at least one component of the exhaust gas can be advantageously identified, particularly in the event of a mixing error.For example, the components are balanced with regard to an overall change, in particular deterioration, in the exhaust gas, and therefore the composition of the exhaust gas. The order is created, for example, using a model also known as a ranking model. One result of the model is, for example, the aforementioned order, also known as the ranking, according to which the components are sorted, for example in ascending or descending order, according to their exhaust gas criticality, i.e. according to their contribution to the change, in particular deterioration, in the composition of the exhaust gas. In particular, the order is created across all exhaust gas-relevant components. This enables robust error detection of malfunctions and / or thus defective components. It is also possible, for example, to classify error severity, particularly in connection with the respective emission influence.

[0018] The procedure is carried out, for example, for several different components of the exhaust gas, for example for CO, NMHC, NOx, etc., so that by determining the respective change value individually for each component of the exhaust gas, an effect or a strength of an effect of the respective component on the respective component of the exhaust gas is determined.

[0019] It has proven particularly advantageous if the respective characteristic map assigns the respective change value to the respective characteristic value for the respective component to which the respective characteristic map is assigned. For example, it is conceivable that the respective characteristic map is designed in such a way that change values, and thus, for example, the change magnitude, are plotted against the characteristic values ​​and thus, for example, against the characteristic value for the respective component.

[0020] In order to be able to diagnose and thus test the drive device in a particularly advantageous manner, it is provided in a further embodiment of the invention that the components comprise the internal combustion engine and / or at least one injector for introducing, in particular directly injecting, a fuel into at least one of the combustion chambers of the internal combustion engine and / or at least one catalyst for aftertreating the exhaust gas and / or at least one lambda probe for measuring a measured variable characterizing a residual oxygen content in the exhaust gas and / or at least one nitrogen oxide sensor for measuring a measured variable characterizing a quantity of nitrogen oxides (NOx) contained in the exhaust gas and / or at least one particle filter for filtering out soot particles from the exhaust gas.

[0021] This ensures particularly advantageous diagnosis of the drive system.

[0022] The internal combustion engine is designed as a gasoline engine or a diesel engine. The particulate filter is therefore designed as a gasoline particulate filter (OPF) or a diesel particulate filter (DPF).

[0023] In order to be able to realize a particularly advantageous diagnosis, it is provided in a further embodiment of the invention that the catalyst has a three-way catalyst and / or an oxidation catalyst and / or an SCR catalyst.

[0024] Alternatively or additionally, the components can comprise a so-called radiator shutter. The radiator shutter is a covering device that is assigned to at least one cooling air opening through which cooling air can flow. The cooling air flowing through the cooling air opening can be fed via the cooling air opening to at least one radiator, by means of which, for example, a coolant, in particular in the form of a liquid, can be supplied for cooling the internal combustion engine in order to cool the coolant via the radiator by means of the cooling air flowing around the radiator. The covering device is movable between a closed position and at least one open position. In the closed position, at least a partial area of ​​the cooling air opening is closed off by the covering device, so that the cooling air can no longer flow through the partial area.In the open position, the cover exposes at least part of the cooling air opening, so that in the open position the cooling air can flow through the partial area.

[0025] Alternatively or additionally, the components may, for example, comprise a secondary air system by means of which air can be introduced as secondary air into an exhaust tract through which the exhaust gas of the internal combustion engine flows, in particular directly, in particular bypassing the, in particular all, combustion chambers of the internal combustion engine.

[0026] Finally, it has been shown to be particularly advantageous for realizing a particularly advantageous diagnosis of the drive device if the characteristic values ​​comprise at least one quantity of oxygen that can be stored in the components, in particular in a three-way catalyst, and thus an oxygen storage capacity value, and / or if the characteristic values ​​comprise at least one value characterizing a response behavior of a lambda probe.

[0027] A second aspect of the invention relates to a motor vehicle, also referred to simply as a vehicle and preferably designed as a motor vehicle, in particular a passenger car, which is designed to carry out a method according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention, and vice versa.

[0028] The invention is based in particular on the following findings and considerations: With the introduction of new emissions standards, such as the so-called EU-7 emissions standard, a reference to an emissions cycle with regard to expected load spectra and cycle-related emission limits can be omitted for OBD errors and thus for emissions-relevant faulty components (OBD - On-Board Diagnostics). In the EU-7 emissions standard, also simply referred to as EU-7, any driving maneuvers are permitted, whereby emission limits must be observed at all times. This can be monitored, for example, using a nitrogen oxide sensor (NOx sensor), especially permanently. In addition, mixture errors are also possible in EU-7.Such a mixing error occurs, for example, when not just one but several of the exhaust-relevant components, or all of the exhaust-relevant components, are defective or have deteriorated, and are therefore malfunctioning. If no appropriate countermeasures are taken, it could be that several exhaust-relevant components have undergone significant ageing, with each component contributing proportionally to a deterioration in the exhaust gas, and therefore to a deterioration in the composition of the exhaust gas. The sum of the individual contributions to the deterioration in the composition of the exhaust gas, also known as exhaust gas deterioration, across the components with different degrees of age can then possibly lead to an emission limit being exceeded if no appropriate countermeasures are taken.

[0029] It has therefore proven particularly advantageous if the change values ​​are compared with one another by means of the electronic computing device when, and preferably only when, for example, a sum of the change values ​​and / or at least one sum value characterizing a sum of the change values ​​exceeds a limit value with which the sum or the sum value is compared by means of the electronic computing device.

[0030] If the aforementioned emission limit value is exceeded, a warning signal is emitted, for example by means of a light source, which is visually perceptible by a person, in particular in the interior of the motor vehicle, in order, for example, to prompt the driver of the motor vehicle to visit a workshop in order to carry out at least one countermeasure there in order to counteract the exceeding of the emission limit value and, in particular, to avoid exceeding the emission limit value in future operation of the motor vehicle.

[0031] The invention is based on the problem existing under EU 7 with a conventional OBD system: determining, among all aged components influencing exhaust gases, which of the components contributes or has contributed most strongly, i.e., most significantly, to the deterioration of the exhaust gas and thus to the exceeding of the emission limit, among all the aged components in the motor vehicle due to the exceedance of the emission limit. One motivation in this regard is, in particular, to only replace, i.e., have replaced, for example, in the aforementioned workshop, the component that has the greatest negative emissions impact and thus the highest exhaust gas criticality with regard to at least one component of the exhaust gas, for example, due to its aging and / or a defect, in order to avoid replacing several components, among which at least one is still fundamentally functional.It is desirable to replace only the component that actually and to an above-average extent affects the deterioration of the exhaust gas composition, for example due to a defect or disproportionately severe aging. This is now possible with the method according to the invention. In particular, the ranking model makes it possible to identify the component with the highest exhaust gas criticality with regard to at least one component of the exhaust gas. This means that, for example, in the event of an exceedance of the emission limit value related to the components, only the component with the highest exhaust gas criticality needs to be replaced. The other, fundamentally still functional components can remain installed, thereby saving costs and resources.

[0032] The invention enables robust fault detection, particularly within the context of OBD. By sequencing all exhaust-relevant components, mixed faults, i.e., fault combinations of multiple defective and / or aged components that are relevant to exhaust emissions, can be robustly detected. This can ensure precise troubleshooting in workshops, as only the component that actually contributes most to exhaust deterioration is replaced. In particular, the invention can realize at least the following advantages: robust fault detection of exhaust-critical components, reduction of costs in a warranty claim, and resource conservation.

[0033] Cost savings through increased efficiency due to faster troubleshooting and better defect component detection

[0034] The ranking model can be implemented in existing control unit structures and only increases the computational effort marginally.

[0035] The method according to the invention can be carried out in a time-efficient manner and can identify the component with the highest exhaust gas criticality, with respect to at least one component of the exhaust gas, in a short time.

[0036] The respective change value characterizes or describes a respective influence of the respective component on the change, in particular deterioration, of the exhaust gas, determined from the characteristic maps of the components and also referred to as the exhaust gas influence. It can be seen that the respective change value is determined at least as a function of the respective characteristic value, which, because the respective characteristic value is determined by the respective diagnostic method, is also referred to as the diagnostic value or diagnostic result. For at least one of the components, such as the lambda sensor, it is conceivable to determine the associated, i.e. assigned, change value exclusively as a function of the associated, i.e. assigned, diagnostic result.For at least other components, such as the catalytic converter, the associated change value can be determined depending on the associated diagnostic result, whereby, for example, the oxygen storage value is used as the diagnostic result for the catalytic converter. The oxygen storage value characterizes an oxygen storage capacity. The oxygen storage capacity is the ability of the catalytic converter to store oxygen and, in particular, indicates the amount of oxygen that can (still) be stored, i.e., storable, in the catalytic converter. The oxygen storage capacity is also referred to as OSC (Oxygen Storage Capacity). Therefore, the characteristic value (diagnostic result) associated with the catalytic converter, for example, is also referred to as the OSC value.It was found that for the additional component, such as the catalytic converter, the change value depends both on the diagnostic result, also referred to as the diagnostic value, which for the catalytic converter is the OSC value, and also on the mass flow of the exhaust gas, also referred to as the exhaust gas mass flow, and on the temperature, in particular of the catalytic converter. The background to this is in particular that, for the same OSC value, a hot catalytic converter aftertreats the exhaust gas better and converts it better than a colder catalytic converter. It is therefore advantageous for the additional component, such as the catalytic converter, not only to determine its or its temperature.its diagnostic result, but at least one or more further influencing variables are to be taken into account, so that, for example, for the further component, such as the catalytic converter, the change value is determined as a function of the assigned characteristic value and also as a function of at least one or more further influencing values, in particular a respective influencing variable. With regard to the catalytic converter, the further influencing variables can be the exhaust gas mass flow and the temperature of the catalytic converter, so that, for example, for the catalytic converter, the further influencing values ​​are a mass flow value characterizing the exhaust gas mass flow and a temperature value characterizing the temperature of the catalytic converter. In this way, the change, in particular deterioration, in the composition of the exhaust gas can be determined with particularly high quality.Overall, it can be seen that with regard to the other component, such as the catalytic converter, a multi-dimensional dependency of the change value can exist. In the case of the catalytic converter, for example, a six-dimensional dependency of the change value exists, since the change value depends, for example, on the aforementioned OSC value, on the exhaust gas mass flow, on the temperature of the catalytic converter, on an increase in a change, in particular an increase and thus a deterioration, in the amount of carbon monoxide (CO) contained in the exhaust gas, on a change, in particular an increase and thus a deterioration, in the amount of nitrogen oxides (NOx) contained in the exhaust gas, and on a change, in particular an increase and thus a deterioration, in the amount of non-methane hydrocarbons contained in the exhaust gas.This is followed, for example, by clustering the dependencies into ranges, such as 500 degrees + / - 50 degrees, 600 degrees + / - 50 degrees, and the same applies to exhaust gas mass flow, particularly with regard to the characteristic maps. At the end of each driving cycle, for example, the factors that impair exhaust emissions are weighted based on a load spectrum analysis (how frequently was the vehicle in which temperature / exhaust gas mass flow ranges during the current cycle, particularly with regard to the catalytic converter). This makes it possible to determine how frequently the vehicle was driven in which characteristic maps and / or at which characteristic map points (load spectrum data is already included in vehicles and is measured).At the end of each driving cycle, for example, an internal output and / or storage of a weighted and sorted, for example ordered, determined exhaust gas deterioration factor for each component and, for example, depending on a frequency of occurrence in the driving cycle takes place.

[0037] Overall, it can be seen that the method according to the invention does not provide for each component to be assigned a potential exhaust gas influence independently of the current state of the respective component. Instead, by taking into account the respective current parameter, the respective current state of the respective component is taken into account in order to determine the respective assigned change value which characterizes, i.e. describes or indicates, the respective influence of the respective component on the change in the exhaust gas. The method therefore makes it possible to identify a component as being most exhaust gas critical if, for example, when all components are new, it has a lower exhaust gas criticality than other components or has the lowest exhaust gas criticality.

[0038] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combinations, but also in other combinations or on their own, without departing from the scope of the invention.

[0039] The drawing shows:

[0040] Fig. 1 is a schematic representation of a drive device of a motor vehicle; and

[0041] Fig. 2 is a block diagram illustrating a method for diagnosing the drive device.

[0042] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0043] Fig. 1 shows a schematic representation of a drive device 10 of a motor vehicle, also simply referred to as a vehicle, whose interior, also referred to as a passenger cell or passenger compartment, is formed, for example, by a structure of the motor vehicle designed in particular as a self-supporting body. The motor vehicle is preferably designed as a motor vehicle, in particular as a passenger car. The drive device 10 has an internal combustion engine 12, here designed as a reciprocating piston engine, by means of which the motor vehicle can be driven. The drive device 10, in particular the internal combustion engine 12, has an intake tract 14 through which air can flow, by means of which the air flowing through the intake tract 14 can be guided to and into the internal combustion engine 12, in particular to and into combustion chambers 16 of the internal combustion engine 12.During fired operation of the internal combustion engine 12, combustion processes occur in the combustion chambers 16. During each combustion process, a respective mixture, also referred to as a fuel-air mixture, is combusted, resulting in exhaust gas from the internal combustion engine 12. The respective mixture includes the air that was fed into the respective combustion chamber 16 via the intake tract. Furthermore, the respective mixture includes a liquid fuel, for example. In the embodiment shown in Fig. 1, the internal combustion engine 12 is designed as a gasoline engine, so that the fuel is a gasoline fuel.

[0044] An air filter 18 for filtering the air flowing through the intake tract 14 is arranged in the intake tract 14. The drive device 10 has, for example, but not necessarily, at least one or exactly one exhaust gas turbocharger 20, which has a compressor 22 arranged in the intake tract 14 for compressing the air flowing through the intake tract 14. The exhaust gas turbocharger 20 can be omitted. The drive device 10 also comprises a recirculation air system 24 with a recirculation air line 26, by means of which at least a portion of the air flowing through the intake tract 14 can be branched off to the intake tract 14 at a first branching point A1 arranged downstream of the compressor 22 and upstream of the combustion chamber 16.The air diverted at branch point A1 can be recirculated to a first inlet point E1 by means of the recirculating air line 26 and reintroduced into the intake tract 14 at the inlet point E1, with the inlet point E1 being located upstream of the compressor 22 and, in this case, downstream of the air filter 18. The recirculating air system 24 also includes a recirculating air valve 28 arranged in the recirculating air line 26, which valve can be operated electrically, for example. The recirculating air valve 28 can be used to adjust the amount of air flowing through the recirculating air line 26.

[0045] The drive device 10, in particular the internal combustion engine 12, also has an exhaust tract 30 through which the exhaust gas from the combustion chamber 16 flows, in which a turbine 32 of the exhaust gas turbocharger 20 is arranged. In particular, via a shaft 34 of the exhaust gas turbocharger 20, the compressor 22 can be driven by the turbine 32, which can be driven by the exhaust gas. A bypass device 36 with a bypass line 38 is assigned to the turbine 32, and the bypass line 38 is fluidly connected to the exhaust tract 30 at a second branch point A2 and a second inlet point E2. The branch point A2 is arranged upstream of the turbine 32 and downstream of the combustion chamber 16, and the inlet point E2 is arranged downstream of the turbine 32. Downstream of the turbine 32, in particular downstream of the inlet point E2, an exhaust gas aftertreatment device 40 is arranged in the exhaust tract 30, which will be explained in more detail below.By means of the bypass line 38, at least a portion of the exhaust gas flowing through the exhaust tract 30 can be branched off from the exhaust tract 30 at the branching point A2 and introduced into the bypass line 38. The exhaust gas introduced into the bypass line 38 and branched off at the branching point A2 can be guided by means of the bypass line 38 to the inlet point E2 and fed back into the exhaust tract 30 at the inlet point E2. It can be seen that the exhaust gas flowing through the bypass line 38 bypasses the turbine 32 and therefore does not drive the turbine 32. The bypass device 36 comprises a bypass valve 42, also referred to as a wastegate or wastegate valve, which is arranged in the bypass line 38. By means of the bypass valve 42, the amount of exhaust gas flowing through the bypass line 38 can be adjusted.In this way, a power of the turbine 32 can be adjusted, whereby a boost pressure to which the air is compressed by means of the compressor 22 can be adjusted.

[0046] The drive device 10 further comprises a secondary air system 44, which has a secondary air line 46. The secondary air system 44 also has a branch line 48. For example, the diverter valve 28 can be a component of the secondary air system 44. At a location designated S1, for example, in the intake tract 14, an air mass meter is arranged, by means of which a quantity, in particular mass, of air flowing through the intake tract 14 can be detected, i.e., measured. The location S1 and thus the air mass meter is arranged, for example, upstream of the compressor 22, in particular upstream of the inlet point E1, and downstream of the air filter 18.

[0047] The branch line 48 is fluidically connected to the intake tract 14 at connection points V1 and V2. A check valve 50, which may be a component of the blow-off air recirculation system 42, is arranged in the intake tract 14 downstream of the connection point V1 and upstream of the connection point V2. The check valve 50 opens the intake tract 14 for a first air flow from the compressor 22 to the combustion chamber 16. The check valve 50 automatically blocks the intake tract 14 for a second air flow that is opposite to the first flow and thus, for example, from the connection point V2 to the connection point V1 and to the compressor 22.

[0048] Arranged in the branch line 48 is a pumping device 52, designed, for example, as a compressor, in particular as an additional compressor, by means of which air can be conveyed from the intake tract 14 in such a way that the pumping device 52, also simply referred to as a pump or air pump, can convey air from the intake tract 14 into the branch line 48 at the connection point V1, convey it through the branch line 48, and convey it back into the intake tract 14 at the connection point V2. The pumping device 52 is preferably electrically operable, thus being an electric pump and preferably an electric compressor.

[0049] The secondary air line 46 is fluidically connected to the intake tract 14 at a third branching point A3. At least a portion of the air flowing through the intake tract 14 and conveyed, in particular compressed, for example, by means of the pump device 52 and / or by means of the compressor 22 can be branched off from the intake tract 14 at the branching point A3 by means of the secondary air line 46 and introduced into the secondary air line 46. The secondary air line 46 is fluidically connected to the exhaust tract 30 at respective third inlet points E3. By means of the secondary air line 46, the air branched off from the intake tract 14 by means of the secondary air line 46 and flowing through the secondary air line 46 can be introduced into the exhaust tract 30 as secondary air at the respective inlet point E3, in particular bypassing the, in particular all, combustion chambers 16 of the internal combustion engine 12.This means that the secondary air on its way from the intake tract 14, through the secondary air line 46 and into the exhaust tract 30 bypasses the, in particular all, combustion chambers 16 of the internal combustion engine 12, and therefore does not flow through the combustion chambers 16, in particular through any combustion chamber of the internal combustion engine 12.

[0050] The secondary air system 44 comprises, for example, secondary air valves 54 arranged in the secondary air line 46, by means of which, for example, a respective amount of secondary air flowing through the secondary air line 46 and / or to be introduced into the exhaust tract 30 at the respective inlet point E3 can be adjusted. Furthermore, a pressure sensor 56 is arranged, for example, in the secondary air line 46, by means of which, for example, a pressure of the secondary air flowing through the secondary air line 46 can be detected.

[0051] In the intake tract 14, a throttle valve 58 is also arranged, which is arranged upstream of the combustion chambers 16 and downstream of the compressor 22, in particular downstream of the branch point A3.

[0052] The exhaust gas aftertreatment device 40 has exhaust gas aftertreatment components 60a-c, by means of which the exhaust gas flowing through the exhaust tract 30 and thus the exhaust gas aftertreatment components 60a-c can be aftertreated. The exhaust gas aftertreatment components 60a-c are thus components that could influence the composition of the exhaust gas and thus the exhaust gas itself. For example, the exhaust gas aftertreatment component 60a is a catalyst, which is designed, for example, as a three-way catalyst. For example, the exhaust gas aftertreatment component 60b is a particulate filter, which, for example, when the internal combustion engine 12 is designed as a gasoline engine, is designed as a gasoline particulate filter (OPF). The exhaust gas aftertreatment component 60c is, for example, a second catalyst, which can be designed, for example, as or comprise a three-way catalyst and / or as an oxidation catalyst and / or as an SCR catalyst.

[0053] From Fig. 2 it can be seen that the drive device 10 also has an electronic computing device 62, also referred to as ECU, by means of which, for example, the internal combustion engine 12 can be operated and thus controlled or regulated.

[0054] With reference to Figs. 1 and 2, a method for diagnosing the drive device 10, which has the internal combustion engine 12 by means of which the motor vehicle is driven, is described below. In particular, the method is carried out by means of the electronic computing device 62. A block 64 illustrates that, for example, an on-board diagnosis (OBD On-Board Diagnostic) is carried out as the diagnosis. In Fig. 2, a block 66 illustrates an air intake, which can be, for example, the intake tract 14. A block 68 illustrates a controller, which, for example, is part of the electronic computing device 62 and is thus implemented by means of the electronic computing device 62. The controller controls, for example, the exhaust gas turbocharger 20.A block 70 illustrates a fuel system by means of which, for example, the internal combustion engine 12, in particular the combustion chambers 16, are supplied with fuel. The fuel system 70 comprises, for example, in particular for each combustion chamber 16, at least one or precisely one injector by means of which the fuel can be introduced, in particular directly injected, into the respective, associated combustion chamber 16. A block 72 illustrates a controller which, for example, controls an injection illustrated by a block 74 and, in this case, for example, the fuel injection system. A block 76 illustrates a tank ventilation system, and a block 78 illustrates a crankcase ventilation system. A block 80 illustrates a controller for camshafts, intake valves, exhaust valves, an injection system, and an ignition system of the internal combustion engine 12.The injection is or comprises, for example, the fuel system and / or the injectors, wherein the fuel is introduced into the combustion chambers by means of the injection, in particular injected directly. The ignition is or comprises, for example, an ignition device, by means of which, for example, at least one respective ignition spark is generated in the respective combustion chamber 16 in order to thereby ignite the respective mixture. The intake valves and the exhaust valves are illustrated by a block 82. A block 84 illustrates spark plugs of the ignition, wherein, for example, a respective one of the spark plugs is assigned to the respective combustion chamber 16, in particular precisely, so that the ignition spark can be generated by means of the respective spark plug assigned to the respective combustion chamber 16 in the respective combustion chamber assigned to the respective spark plug. The injection is illustrated by a block 86. A block 88 illustrates a battery and a DC-DC converter.A block 90 illustrates a cooling water thermostat, and a block 91 illustrates a starter-generator. Blocks 92, 94, and 96 illustrate sensors of the drive device 10, wherein the sensors are arranged, for example, in the exhaust tract 30. The sensor illustrated by block 92 is, for example, a first lambda probe, and the sensor illustrated by block 94 is, for example, a second lambda probe. The first lambda probe is arranged downstream of the combustion chambers 16 and upstream of the exhaust gas aftertreatment component 60a, and the second lambda probe is arranged downstream of the exhaust gas aftertreatment component 60a and upstream of the exhaust gas aftertreatment component 60b. The sensor illustrated by block 96 is, for example, a nitrogen oxide sensor, which is arranged downstream of the exhaust gas aftertreatment component 60b. A block 98 illustrates a controller for regulating the first lambda probe.Finally, a block 100 illustrates a controller for controlling the second lambda probe.

[0055] Overall, it can be seen that the drive device 10 has components by means of which the composition of the exhaust gas of the internal combustion engine 12 can be influenced and / or detected. The sensors mentioned are, for example, components that can detect the composition of the exhaust gas. Detecting the composition of the exhaust gas means that the respective component that can detect the composition of the exhaust gas can detect at least one measured variable that characterizes at least one chemical substance contained in the exhaust gas and thus at least one component of the exhaust gas.The components that can influence the exhaust gas of the internal combustion engine 12 include, for example, the internal combustion engine 12 itself, the exhaust gas aftertreatment components 60a-c and, for example, the injection and / or the ignition and / or the intake valves and / or the exhaust valves and / or the camshafts and / or the fuel system and / or the air intake and / or the secondary air system 44 and / or the spark plugs and / or the throttle valve 58 and / or a coolant, for example in the form of cooling water, for cooling the internal combustion engine 12 and / or the battery and / or the DC-CC converter and / or the starter generator.

[0056] In the aforementioned method for diagnosing the drive device 10, at least one respective diagnostic method assigned to the respective component and also referred to as an individual diagnostic method or individual diagnosis is carried out by means of the electronic computing device 62 for the respective component which can detect and / or influence the composition of the exhaust gas. This diagnostic method is also referred to as an individual diagnostic method or individual diagnosis. For the respective component to which the respective diagnostic method is assigned, at least one respective current characteristic value, in particular a characteristic variable, is determined, wherein the respective current characteristic value characterizes a respective current state of the respective component. At least one current change value is determined by means of the electronic computing device 62, wherein the current change value characterizes a current composition of the exhaust gas of the internal combustion engine 12.By means of the electronic computing device 62, a respective change value assigned to the respective component for the respective components of the exhaust gas is determined for the respective component, in particular based on a respective initial value of a respective constituent of the exhaust gas of a component, which is determined in particular when the component is new, and as a function of the respective current characteristic value assigned to the respective component and as a function of at least one respective characteristic map stored in the electronic computing device 62 and assigned to the respective component, which change value characterizes a change in the composition of the exhaust gas and thus of the exhaust gas itself that can be brought about by the respective component. By means of the electronic computing device 62, the change values ​​are compared with one another, whereby the largest of the change values ​​is determined.The component to which the largest change value is assigned has the highest exhaust gas criticality in relation to all the components. This means that the component to which the highest change value is assigned contributes most strongly to a particularly negative change in the composition of the exhaust gas. In the method, an entry is stored in a data memory of the electronic computing device for the component to which the largest change value is assigned. Alternatively or additionally, an indication signal that can be perceived visually and / or haptically and / or acoustically by a person in the interior of the motor vehicle is specifically output for the component to which the largest change value is assigned, in particular by means of an electronic or electrical playback device of the motor vehicle.The entry and / or the warning signal instructs the person and / or another person performing repair or maintenance on the motor vehicle to replace the component, and preferably only the component, associated with the largest change value, while the other components can remain installed. This can ensure, for example, low-emission operation of the drive system 10 for future operation without replacing all or several of the components.

[0057] List of reference symbols

[0058] 10 Drive device

[0059] 12 Internal combustion engine

[0060] 14 Intake tract

[0061] 16 combustion chamber

[0062] 18 air filters

[0063] 20 exhaust gas turbochargers

[0064] 22 compressors

[0065] 24 recirculation system

[0066] 26 recirculation air line

[0067] 28 Diverter valve

[0068] 30 Exhaust system

[0069] 32 turbines

[0070] 34 Wave

[0071] 36 Bypass facility

[0072] 38 bypass line

[0073] 40 exhaust aftertreatment system

[0074] 42 Bypass valve

[0075] 44 Secondary air system

[0076] 46 Secondary air line

[0077] 48 branch line

[0078] 50 check valve

[0079] 52 Pumping device

[0080] 54 Secondary air valve

[0081] 56 Pressure sensor

[0082] 58 Throttle valve

[0083] 60 ac exhaust aftertreatment component

[0084] 62 electronic computing device

[0085] 64 blocks

[0086] 66 Block

[0087] 68 Block

[0088] 70 blocks

[0089] 72 Block

[0090] 74 Block

[0091] 76 Block

[0092] 78 Block 80 Block

[0093] 82 Block

[0094] 84 Block

[0095] 86 Block

[0096] 88 Block

[0097] 90 blocks

[0098] 91 Block

[0099] 92 Block

[0100] 94 Block

[0101] 96 Block

[0102] 98 Block

[0103] 100 blocks

[0104] A1 first junction

[0105] A2 second junction

[0106] A3 third junction

[0107] E1 first discharge point

[0108] E2 second discharge point

[0109] E3 third discharge point

[0110] V1 connection point

[0111] V2 connection point

Claims

Patent claims 1. A method for diagnosing a drive device (10) having an internal combustion engine (12) of a motor vehicle that can be driven by the internal combustion engine (12), in which: - the drive device (10) has components (60a-c) by means of which a composition of exhaust gas of the internal combustion engine (12) can be influenced and / or detected; - by means of an electronic computing device (62) for the respective component (60a-c), at least one respective diagnostic method assigned to the respective component (60a-c) is carried out, by means of which at least one respective current characteristic value assigned to the respective component (60a-c) is determined for the respective component (60a-c) to which the respective diagnostic method is assigned, which characteristic value characterises a respective current state of the respective component (60a-c); - by means of the electronic computing device (62) for the respective component (60a-c) for the current characteristic value assigned to the respective component (60a-c), a respective change value assigned to the respective component (60a-c) and related to a respective initial value is determined for a respective component of the exhaust gas as a function of at least one respective characteristic map stored in the electronic computing device (62) and assigned to the respective component (60a-c), ; - the respective change values ​​of the components (60a-c) are compared with each other by means of the electronic computing device (62), whereby the largest of the respective change values ​​is determined; and - for the component (60a-c) to which the largest of the change values ​​is assigned: o an entry is stored in a data memory of the electronic computing device (62); and / or o an information signal that can be perceived visually and / or haptically and / or acoustically by a person is output by means of a playback device of the motor vehicle.

2. Method according to claim 1, characterized in that: - by means of the electronic computing device (62), the respective change value is compared with a respective assigned limit value, wherein: o the change values ​​are compared with one another by means of the electronic computing device if it is determined by comparing the respective change value with the respective limit value that at least one of the change values ​​exceeds the respectively assigned limit value; and / or o an error entry is stored and / or a further indication signal is output for the component (60a-c) to which the largest of the change values ​​is assigned if it is determined by comparing the respective change value with the respective limit value that at least one of the change values ​​exceeds the respectively assigned limit value; and / or - the change values ​​are summed up by means of the electronic computing device (62), whereby a sum value is formed which is compared by means of the electronic computing device with the assigned limit value, wherein: o the change values ​​are summed up by means of the electronic computing device if it is determined by comparing the sum value with the limit value that the sum value exceeds the limit value; and / or o the error entry is stored and / or the further indication signal is output for the component (60a-c) to which the largest of the change values ​​is assigned if it is determined by comparing the sum value with the limit value that the sum value exceeds the limit value.

3. Method according to claim 1 or 2, characterized in that by means of the electronic computing device (62) the change values ​​are sorted in ascending or descending order by comparing the change values.

4. Method according to one of the preceding claims, characterized in that the respective characteristic map for the respective component (60a-c) to which the respective characteristic map is assigned, assigns the respective change value to the respective characteristic value.

5. Method according to one of the preceding claims, characterized in that the components (60a-c) comprise: - the internal combustion engine (12) and / or - at least one injector for introducing a fuel into at least one combustion chamber (16) of the internal combustion engine (12) and / or - at least one catalyst for aftertreating the exhaust gas and / or - at least one lambda probe for measuring a measured variable characterising a residual oxygen content in the exhaust gas and / or - at least one nitrogen oxide sensor for measuring a quantity characterising a quantity of nitrogen oxides contained in the exhaust gas and / or - at least one particulate filter to filter out soot particles from the exhaust gas.

6. The method according to claim 5, characterized in that the catalyst comprises a three-way catalyst and / or an oxidation catalyst and / or an SCR catalyst.

7. Method according to one of the preceding claims, characterized in that the characteristic values ​​comprise: - at least one oxygen storage value which characterises an amount of oxygen that can be stored in at least one of the components, and / or - at least one value characterising the response behaviour of a lambda probe.

8. Motor vehicle which is designed to carry out a method according to one of the preceding claims.

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